Archive for February 25th, 2009

“Let us consider for a moment you are driving down the road and approaching a signalized junction. The scene in front of you is a dynamic one and is constantly evolving. The light is at present green but of course this may change. The intersection is also currently clear, but of course this may also change. Now let us run the scenario forward. As you approach the actual crossing, the visual angle between the traffic light and the forward view across the junction begins to increase. There comes a point in time where one cannot see both together. This is not a divided attention issue or one or foveal versus peripheral field of view, it is a simple question of structural interference, the driver’s eye cannot see both at the same time. The design efforts of traffic engineers in terms of sight lines, seek to reduce any such occurrences of ambiguity, and on most occasions they are very successful. However, let us consider this example as one of inherent ambiguity. Where is the driver to look? If you look at the light to see a possible change, one cannot look at the intersection and vice versa. The pragmatist will say that by the time the light changes, the junction should be free. However, the simple fact is that driving presents many such ambiguous situations in which, whatever “correct” action one is actually accomplishing, there is another equally “correct” action that one must neglect. What of distraction in such circumstances? Can we say the driver involved in a collision in such circumstances is distracted and is not driving with due care and attention?”

That’s one of the many interesting bits of a paper by P.A. Hancock, M. Mouloua, & J.W. Senders, “On the philosophical foundations of driving distraction and the distracted driver,” in a recent book titled Driver Distraction: Theory, Effects, and Mitigation.

The earlier posting on late merging reminds reader Joel of the issue of “lane splitting,” by which motorcyclists (and sometimes bicyclists) ride in the space between cars, ideally in heavy traffic. This is legal in California and other states, but, as he points out, it seems to raise drivers’ hackles (in places like Rome, of course, it’s an everyday fact of life, as scooters by the dozens “filter” between cars to settle near the front of stopped queues at traffic lights).

It’s an interesting, much-discussed issue (see here or here for example) because it raises so many of the issues that come up in traffic: Social justice (hey, why are they allowed to move when I’m stuck in traffic), different modes sharing the same road space, trading off risks, not to mention cognitive psychology.

Like so many things in traffic, it’s complex. In theory, I like the idea — why shouldn’t we use as much road space as possible? (the extra lane space put in for safety at high speeds is essentially wasted during congestion). A motorcycle between streams of cars shortens the length of the queue for cars, after all (and unlike HOV or hybrid lanes, doesn’t reduce existing highway space). On the other hand, there have been times when I’ve been absolutely startled by a motorcyclist unexpectedly passing me. This raises the question of the “attentional set”: If we don’t usually expect motorcycles to be there, will we not see them as we change lanes, or if we unintentionally “drift” a bit? (for the biker, the added problem is the people who don’t signal before changing).

And yet the smaller visual profile of motorcycles means we may not see them in front of us as easily as a car — not to mention the fact that the small fender-bender of stop-and-go traffic means more to a cyclist’s health than a car driver’s — and this brings up the point that has always been made vis a vis lane splitting: That being rear-ended by a car is a much greater hazard than riding between the lanes. The leading authority on this, and motorcycle safety in general, is Harry Hurt, author of the famous “Hurt Report” and now based here, who is quoted here as saying: “For a motorcyclist, that’s the safest place to be [between streams of traffic]… A lot of people think it’s a hazard, but the cold, hard facts are that it’s not.”

As far as I know, the “Hurt Report” has never been duplicated in size or scope, even as more motorcyclists have hit the road. The author himself seemed to think its 1970s-era findings, however, still hold valid.

As it happens, yesterday I was just reading a piece in Outside about the idea of bringing Asian-style “motorcycle taxis” to the U.S. The piece notes:

In the U.S., moto-taxis face two main obstacles. The first is insurance. When EagleRider, now the largest motorcycle-rental company, initially shopped for insurance, their rates were three times what they’re paying now. The second problem is a traffic law in 37 states that bans “splitting”—the practice of riding between lanes. Sounds unsafe, but even when allowed, it accounts for only 3 percent of motorcycle fatalities. When it’s outlawed, you’re stuck in crosstown traffic just like everyone else, only you’re breathing exhaust.

The 3% number is interesting; then again, if lane-splitting was only done when it is supposed to be, during slow or stopped heavy traffic, I wouldn’t expect large numbers of fatalities.

Any motorcyclists out there care to weigh in? Cyclists? Drivers? People selling things at traffic lights? (they too lane split)

And just to muddy the waters, speaking of social justice and road sharing, I’ve been annoyed lately to see motorized scooters chugging along in the bike lanes in Brooklyn and elsewhere. My knee-jerk reaction is ‘that’s not what their for” and ‘I don’t want your exhaust in my face’; but maybe I’m too harsh — perhaps if it’s otherwise unoccupied it’d be OK. But while it may make them feel safer, they may only be raising their exposure to “dooring” and other hazards.

This post combines two of my recent obsessions — the atomic landscape and traffic (not to mention plugging my previous book), and the advertising image shown is typical of the times — playing on deep nuclear paranoia to help push a corporate agenda.

There’s an academic article, if not already done, to be written on the appearance of the mushroom cloud or other intimations of nuclear holocaust in 1950s advertising — I even have one in my collection for a paint company ‘now what should we paint the bedroom, honey? Nuclear winter?’ (no, it doesn’t really say that); in any case a mushroom cloud is no doubt more effective an image for road building than rote statistics about lost productivity.

In light of recent evacuation troubles (e.g., Katrina in New Orleans) with anticipated natural disasters, it’s hard to imagine that in a surprise strike on major population centers a nice new ribbon of asphalt would have really meant much to the average citizen.

Still, if you were going to hit the road, a “Survival Car” might have come in handy.

How We Drive is the companion blog to Tom Vanderbilt’s New York Times bestselling book, Traffic: Why We Drive the Way We Do (and What It Says About Us), published by Alfred A. Knopf in the U.S. and Canada, Penguin in the U.K, and in languages other than English by a number of other fine publishers worldwide.